Browsing by Author "Chen, L."

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    Studies on slurry design fundamentals for advanced CMP applications
    (ECS, 2013) Başım, Gül Bahar; Karagöz, Ayşe; Özdemir, Zeynep; Vakarelski, I. U.; Chen, L.; Mechanical Engineering; BAŞIM DOĞAN, Gül Bahar; Karagöz, Ayşe; Özdemir, Zeynep
    New developments and device performance requirements in microelectronics industry add to the challenges in chemical mechanical planarization (CMP) process. One of the recently introduced materials is germanium which enables improved performance through better channel mobility in shallow trench isolation (STI) applications. This paper reports on the slurry design alternatives for Ge CMP with surfactant mediation to improve on the silica/germanium selectivity using colloidal silica slurry. In addition to the standard CMP tests to evaluate the material removal rates, atomic force microscopy (AFM) based wear tests were also conducted to evaluate single particle-surface interaction of the polishing system. Furthermore, nature of the surface oxide film of germanium was studied through contact angle measurements and surface roughness tested by AFM. It was observed that the CMP selectivity of the silica/germanium system and defectivity control were possible with a reasonable material removal rate value by using self-assembled structures of cationic surfactants.
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    Surfactant mediated slurry formulations for Ge CMP applications
    (Cambridge University Press, 2013) Başım, Gül Bahar; Karagöz, Ayşe; Chen, L.; Vakarelski, I.; Mechanical Engineering; BAŞIM DOĞAN, Gül Bahar; Karagöz, Ayşe
    In this study, slurry formulations in the presence of self-assembled surfactant structures were investigated for Ge/SiO2 CMP applications in the absence and presence of oxidizers. Both anionic (sodium dodecyl sulfate-SDS) and cationic (cetyl trimethyl ammonium bromide-C12TAB) micelles were used in the slurry formulations as a function of pH and oxidizer concentration. CMP performances of Ge and SiO2 wafers were evaluated in terms of material removal rates, selectivity and surface quality. The material removal rate responses were also assessed through AFM wear rate tests to obtain a faster response for preliminary analyses. The surfactant adsorption characteristics were studied through surface wettability responses of the Ge and SiO2 wafers through contact angle measurements. It was observed that the self-assembled surfactant structures can help obtain selectivity on the silica/germanium system at low concentrations of the oxidizer in the slurry.